Retractable blade knife



FIG. 1 is a perspective view of a retractable blade knife, showing mynew design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a left side elevational view thereof; and,

FIG. 6 is a right side elevational view thereof.

The ornamental design for a retractable blade knife, as shown anddescribed.